Speaker
Description
Type Ia Supernovae (SNIa) are fundamental distance indicators for cosmology thanks to their nature as standardizable candles. The Rubin Observatory Legacy Survey of Space and Time will provide a sample of millions of SNIa due to its large sky coverage and high cadence. Apart from the direct measurement of cosmological parameters with traditional methods of SNIa analysis, this sample enables the study of peculiar velocities to probe the growth rate of structures in the universe. These velocities are caused by the gravitational attraction of the large-scale structure of the universe: as galaxies tend to move towards denser regions, objects in the same region of the sky have correlated velocities. These correlations can be employed to study the intensity of the gravitational interaction on large scales. Current techniques rely on traditional three-dimensional statistical estimators for the data analysis. However, these estimators are inconvenient for application to Rubin LSST data, which will use angular power spectra to extract cosmological signals from galaxy overdensities and gravitational lensing. In this study, we will apply the Fisher information matrix methodology to the angular power spectrum of SNIa peculiar velocities. The main goal is to demonstrate the viability of using this estimator for the expected Rubin LSST data. We will investigate scenarios with velocities alone, and in combination with galaxy density and gravitational lensing observables. This is a first step towards future measurements of cosmological parameters using a combination of Type Ia supernova peculiar velocities and 3x2pt cosmological estimators in the context of Rubin LSST.